Sheet-feeding device



June 22, 1965 A. SCHWEBEL 3,190,644

SHEET-FEEDING DEVICE Filed Dec. 12, 1962 INVENTOR. A001. F SCHWEBEL BYHQMC/MW United States Patent firm Filed Dec. 12, 1962, Ser. No. 244,195 Claims priority, application Germany, Jan. 27, 1961, M 51,319 6 Claims. (Cl. 271-46) The present invention relates to a sheet-feeding device for printing presses and other sheet processing machines, and more particularly to a device for aligning or orienting the sheets fed by the sheet feeder of a printing press or other sheet processing machine. The sheet feeder may for instance be pneumatically operated.

The rate of the feeding speed and the spacing with which sheets are fed to the alignment markers or pins of a printing machine or other sheet processing machine are selected in accordance with the type of the paper sheets and the size thereof. In order to assure correct alignment of the sheets at the front markers or pins of the machine, there are known devices for retarding the normal rate of the feeding speed and even for temporarily halting the feed of the sheets. However, such aligning devices as heretofore known require various, rather complex structural components such as elliptical gears, cams, oscillatory gearings, etc. There are also known devices which employ gear trains for stepping down the rate of feeding to the desired rate when the sheets are close to the markers of the aligning device.

As is evident, complex devices of this kind cause a substantial increase in the total costs of the sheet processing machine and also in the maintenance costs. They also reduce the range of usefulness of the machines and the capacity thereof since modern high speed feeding of sheets tends to cause slippage and rebounding of sheets. Furthermore, practical experience shows that sheet aligning devices as heretofore known, tend to cause not infrequently structural damage to the sheet processing machine itself, particularly to the cylinders of a printing press. Also, the starting of machines equipped with the aforementionedcornplex aligning devices is timeconsuming and requires highly skilled lab or.

It is a broad object of the invention to provide a novel and improved sheet-feeding device for use with sheet processing machines which is inexpensive in construction, simple and reliable in operation and compatible with existing conventional printing presses and the other sheet processing machines and the alignment markers or pins thereof.

A more specific object of the invention is to provide a novel and improved sheet feeding device which merely requires movement of a few and very light components. This affords the advantage that a high speed feeding can he maintained without adversely affecting the quality of the output of the machine.

Another more specific object of the invention is to provide a novel and improved sheet-feeding device which automatically forces sheets reaching the markers or pins of the machine in a misaligned position into the correct position.

The aforementioned objects, features and advantages of 3,196,644 Patented June 22, 1965 the invention and other objects, features and advantages which will he pointed out hereinafter are attained by providing between the markers and a main conveyor for feeding the sheets an auxiliary feed conveyor which reduces the rate of feed shortly before the leading edge of the sheets reaches the markers.

The invention further encompasses alignment means interposed between the markers and the main conveyor and coacting with the auxiliary conveyor, said means gripping a sheet approaching the markers on the auxiliary conveyor and automatically turning a misaligned sheet into the correct position in reference to the markers.

in the accompanying drawing several preferred embodiments of the invention are shown by way of illustration and not by Way of limitation.

In the drawing:

FIG. 1 is a diagrammatic elevational view, partly in section, of a sheet feeding device according to the invention.

FIG. 2 is a plan View of FIG. 1 (the sheets shown in FIG. 1 are omitted in FIG. 2 for clarity of illustration), and

PEG. 3 is a fragmentary view, partly in section, of a modification of the sheet-feeding device according to the invention.

Referring first to FIGS. 1 and 2 in detail, the sheetfeeding device according to these figures comprises a table 1 upon which are placed several sheets 23 to be fed. The sheets may be for instance paper sheets which partly overlap each other. Transport of the sheets is from right to left and is effected by means of two belt drives 2. The belt drives are guided over and tensioned by several pulleys 30 and a driven pulley 3 which is rotated by any suitable drive means indicated at 31. The sheets are held against the table by pressure rollers 11, all or some of which may also be driven. The position of the rollers in respect to the table is preferably adjustable to permit adjustment of the holding pressure in accordance with the type of sheets to be fed. At the end of the feed path formed by conveyor belts 2, there are provided marker pins 8 and 3 which are transversely spaced in reference to the direction of travel of the sheets. In the gap between the markers and the end of the feed path there is mounted an auxiliary conveyor formed by two transversely spaced belts 5 guided on pulleys s, 6' and 7. Pulley 6 is shown as being driven by a suitable drive means indicated at 32. The speed with which the auxiliary conveyor is driven is less than the speed of the main conveyor. Hence the rate of feed by the auxiliary conveyor is slower than the rate of feed by the main conveyor. In this connect-ion it should be pointed out that while two drive means 31 and 32 are shown, this is only to indicate that the rate of speed of the two conveyors is different from each other. Obviously the slower speed of belts 5 and 5 can be obtained by providing two drive means, or by providing a common drive means including appropriate transmission means.

As is evident, the forward feed of each sheet is slowed as soon as its leading part leaves belts 2 and reaches belts 5 and 5'. One of pressure rollers 11 is preferably so placed that the leading part of each sheet reaches belts 5 and 5' before the trailing part of the sheet becomes free of that pressure roller 11. The sheets are preferably guided on belts 5 and 5 by ball riders or rollers 24 capable of following the movements of the sheets. As a result of the actions of the aforementioned rollers 11 and guides 24 a sheet will continue in its direct-ion of travel when reaching belts 5 and 5 though at a reduced rate of speed.

Assuming first that a sheet is in the correct position when driven first by belts 2 and then by belts 5 and 5. Such sheet will eventually reach markers 8 and 8 in the correct position and may then be withdrawn for further operations. However, a sheet may be misaligned on the table, in particular angled in reference to the direction of travel. As pointed out before, it is an object of the invention to correct automatically such misalignment of sheets. The means provided for this purpose comprise a suction box 4 in which are formed by partition walls two suction chambers 21 and 21. Each suction chamber has in its top wall, that is the wall facing belts 5 and 5 respectively slots 12, and the belts themselves are perforated as is clearly shown in FIG. 2. Each suction chamber is connected to a suction pipe 14 which should be visualized as being connected to a suitable source of suction such as a vacuum pump. The suction in each suction pipe is controlled by means of a valve 13 in which a valve body 15 is rotatable. The position of each valve body is controlled by a solenoid 18, the armature 17 of which is coupled with the valve body 15 by any suitable means such as a rack and a toothed segment 16. Each solenoid 18 is connected in an energizing circuit including a source of current 32 and switch contacts 19 and 29 of a switch 10. The switch contacts are controlled by a movable contact arm 9 which protrudes into the path of a sheet approaching marker 8. Contact arm 9 is biased into a position 7 in which contacts 19 and 20 are open.

As is evident, the entire just-described control mechanism is provided for each of the belts 5 and 5'. The corresponding components are indicated by primed numerals.

The operation of the device as hereinbefore described, is as follows:

Let it be assumed that the foremost sheet is correctly aligned as it reaches belts 5 and 5'. The gripping action due to the suction in chambers 21 and 21 will pull the sheet somewhat against the belts, but will not change its orientation. Accordingly, the leading edge of the sheet will engage eventually contact arms 9 and 9' simultaneously thereby closing contacts 19, 20 and 20, 20. As a result the solenoids 18 will both turn both valves into the position closing conduits 14, and the gripping action at both belts 5 and 5' will disappear. When the leading edge reaches both markers 8 and 8' shortly thereafter the sheet may be withdrawn for further operation as previously described.

Let it now be assumed that a sheet reaching belts 5 and 5' is misaligned and that the top leading corner of the sheet is the forward one. Accordingly, this corner will reach and operate contact arm 9 and thus releasing the suction in chamber 21 whereas the suction in chamber 21 and hence the gripping action at belt 5' is maintained. As a result, the sheet will be automatically turned in clockwise direction until the lower leading edge of the sheet engages contact arm 9 also thereby releasing the gripping action at belt 5'. In other words, a misaligned sheet will be first forced into the correct position and it will then be released from the gripping action at both belts 5 and 5' for further operation in the manner previously described.

The device as shown in FIG. 3 operates in basically the same manner except that the two belts 5 and 5' are replaced by a rotary perforated drum 25 in which two transversely spaced suction chambers 26 and 27 are formed. The control mechanism of the device according to FIG. 3 is the same as has been described in connection with FIGS. 1 and 2. In other words, chambers 26 and Car 27 correspond in function to suction chambers 21 and 21'.

The function of the device according to FIG. 3 is evident from the previous description.

While the invention has been described in detail with respect to certain now preferred examples and embodiments of the invention it will be understood by those skilled in the art after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and modifications in the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

I claim:

1. A sheet-feeding device for sheet processing machines, said device comprising a main conveyor means for feeding sheets placed thereupon along a feed path, marker means at the end of said feed path spaced therefrom by a gap, an auxiliary conveyor means disposed in said gap for feeding sheets from the end of said feed path toward abutment with said marker means, said auxiliary conveyor means feeding sheets placed thereupon at a lower rate of feed than said main conveyor means, an aligning means disposed in said gap, said aligning means including a pair of normally actuated but releasable sheet gripping means disposed spaced apart transverse of the direction of travel of the sheets on said conveyor means, and a control means including a release means for each of said gripping means, said release means being disposed transversely spaced apart anterior of the marker means for engagement with the leading edge of the foremost sheet, engagement of said leading edge with both release means effecting release of both gripping means and engagement of said leading edge with one release means due to misalignment of the sheet effecting release of the respective gripping means only, whereby the misaligned sheet is caused to turn about the still actuate-d gripping means as fulcrum into a position of alignment in which the second release means is also engaged for effecting release of said still actuated gripping means.

2. A sheet-feeding device according to claim 1 wherein each of said gripping means comprises a suction means acting upon a sheet traveling upon said auxiliary conveyor means to hold said sheet against said conveyor means, and wherein each of said control means comprises switch means controlled by engagement with the leading edge of a sheet and controlling said suction means to render the same inactive upon operation of the respective switch means.

3. A sheet-feeding device according to claim -2 wherein said auxiliary conveyor means comprising a pair of transversely spaced perforated belt drives driven at a lower speed than the main conveyor means, and wherein each of said suction means comprises an open suction chamber disposed between one of said belt drives and connccted to a suction conduit, and wherein each of said control means comprises an electro-magnetically operated valve controlled by operation of said switch means and controlling the respective suction conduit.

4. A sheet-feeding device according to claim 3 wherein said switch means comprises a movable contact arm controlling switch contacts and extending closely adjacent to the marker means into the path of sheets traveling on said auxiliary conveyor means, said contact arm being moved in reference to the switch contacts by engagement with the leading edge of a sheet just before said edge reaches said marker means.

5. A sheet-feeding device according to claim 2 wherein said auxiliary conveyor means comprise a perforated rotary drum driven at a lower speed than said main conveyor means, and wherein each of said suction means comprises an open suction chamber disposed Within said drum, said chambers being transversely spaced apart with the leading edge of a sheet just before said edge reaches said marker means.

References Cited by the Examiner UNITED STATES PATENTS 555,422 2/96 Van Benthuysen 271-50 2,033,320 3/36 Belluche 27146 2,313,100 3/43 Stevens 271-27 10 ROBERT B. REEVES, Acting Primary Examiner.

RAPHAEL M. LUPO, Examiner. 

1. A SHEET-FEEDING DEVICE FOR SHEET PROCESSING MACHINES, SAID DEVICE COMPRISING A MAIN CONVEYOR MEANS FOR FEEDING SHEETS PLACED THEREUPON ALONG A FEED PATH, MARKER MEANS AT THE END OF SAID FEED PATH SPACED THEREFROM BY A GAP, AN AUXILIARY CONVEYOR MEANS DISPOSED IN SAID GAP FOR FEEDING SHEETS FROM THE END OF SAID FEED PATH TOWARD ABUTMENT WITH SAID MARKER MEANS, SAID AUXILIARY CONVEYOR MEANS FEEDING SHEETS PLACED THEREUPON AT A LOWER RATE OF FEED THAN SAID MAIN CONVYOR MEANS, AN ALIGNING MEANS DISPOSED IN SAID GAP, SAID ALIGNING MEANS INCLUDING A PAIR OF NORMALLY ACTUATED BUT RELEASABLE SHEET GRIPPING MEANS DISPOSED SPACED APART TRANSVERSE OF THE DIRECTION OF TRAVEL OF THE SHEETS ON SAID CONVEYOR MEANS, AND A CONTROL MEANS INCLUDING A RELEASE MEANS FOR EACH OF SAID GRIPPING MEANS, SAID RELEASE MEANS BEING DISPOSED TRANSVESELY SPACED APART ANTERIOR OF THE MARKER MEANS FOR ENGAGEMENT WITH THE LEADING EDGE OF THE FOREMOST SHEET, ENGAGEMENT OF SAID LEADING EDGE WITH BOTH RELEASE MEANS EFFECTING RELEASE OF BOTH GRIPPING MEANS AND ENGAGEMENT OF SAID LEADING EDGE WITH ONE RELEASE MEANS DUE TO MISALIGNMENT OF THE SHEET EFFECTING RELEASE OF THE RESPECT GRIPPING MEANS ONLY, WHEREBY THE MISALIGNED SHEET IS CAUSED TO TURN ABOUT THE STILL ACTUATED GRIPPING MEANS AS FULCRUM INTO A POSITION OF ALIGNMENT IN WHICH THE SECOND RELEASE MEANS IS ALSO ENGAGED FOR EFFECTING RELEASE OF SAID STILL ACTUATED GRIPPING MEANS. 